I think the easy way would be to use your audio interface to do this but it will depend on the interface you use. With my fireface I could have a master mix sent to my monitors and then send each of the busses off to different outs which can be summed for the headphone mix.

Karhide, sounds like us RME guys think the same. RME Total Mix makes it completely easy to have a different mix of every pair of outs from the interface using TotalMix.
 
I know I could have done a single mix with my M-Audio if I wanted to, but I couldn't do a control room mix that differed from the drummers mix that differed from the vocalists mix (which we can do with RME TotalMix).
 
In this link, RME likens TotalMix to Cubase and say they used Cubase's Routing Logic as a jumping off place for TotalMix.
 
It makes me wonder how this same question would be answered on a Cubase Forum.
 
Right now, I'm imagining a case where you select your output bus in Sonar and you get an entirely different set of FX, Sends, Busses, automation envelopes etc. You could have as many full mixes as you have interface output pairs. You could have things in common across all mixes or specific to certain mixes. You could copy a mix to a new output pair on your interface and go to town, then A/B the two outputs! Now, this would push the load on the PC through the Ceiling -- 10 copies of all your FX and Routing and Synths all running at the same time... haha. Wahoo!!
 
But, to tell the truth, I don't think I'd ever use this in Sonar if we had it. I'd just use my RME exactly as described.

To the OP,
 I am intrigued.
 
 What software had the feature you describe in your first post?
 
 I've had the same frustration you are describing.
 
 I usually get the first project set up for the day and then make a project template of those routings and efx etc. and then I drag and drop (as you mentioned) from previous project files in to the newer template. It's sort of a pain but it's the least painful way I know of to do it when you have, as you described, a bunch of projects to do it too.
 
 I've never sweated it too much because I like to monitor through SONAR with all the same effects I mix with so the effort seems worth it. All things considered I feel lucky that I'm not mixing with a mid grade console and  bunch of mid grade hardware so I do the drag and drop thing as if it is a matter of course..
 
 I'd like to know where you were able to use the features you described as being available in some other DAW. It sounds pretty cool.
 
 Thanks.
 
 
 best regards,
mike

rianneloff:
 
I understood what you meant.  If you use my method, you can save the project exactly the way in which you described.  You'll have the "main mix" saved and you'll have the head phone mix saved because each instrument will be routed to its own "headphone bus," so if you save it, the panning, volume, etc will be saved and won't affect the main mix.....

MelodicJimmy
rianneloff:
 
I understood what you meant.  If you use my method, you can save the project exactly the way in which you described.  You'll have the "main mix" saved and you'll have the head phone mix saved because each instrument will be routed to its own "headphone bus," so if you save it, the panning, volume, etc will be saved and won't affect the main mix.....

 
I think the problem for me with this method is what you mentioned - I use several buses for fx. However, the op could create a tracking template like you described.